When you get a lump sum of money that you intend on saving, you want to be sure you invest it well and get the maximum return for your money. While this is a good notion, money blog 20 Something Finance explains why it's not the most important number you should focus on.

The blog explains how it's easy to get distracted by an influx of money. When you sell your car, get a bonus, or just finally accumulate a decent amount of savings, it's tempting to think that you've got this savings thing sorted out and now it's time to let interest take over. The author explains why this is a flawed mentality:

Here's the thing: when you have low asset levels, personal savings rate > investment rate of return. Actually, I think that's a bit of an under-statement, so lets try this: personal savings rate is 90% of the battle. Investment returns (i.e. asset allocation A vs. asset allocation B) are comparatively insignificant. Sadly, the average personal savings rate for Americans is now at 3.9%.

If you want financial independence, personal savings rate should be priority #1, 2, and 3 to get you there. And 3.9% isn't anything close to being able to cut it.

And this stays true until one amasses a few hundred thousand dollars in assets or more. When one reaches those levels, then investment returns start having a much larger impact, and at some point can even surpass non-investment income.

While maximizing your ROI is great, the long-term effects won't really be felt until you've reached a critical mass of savings. The difference between an 8% and a 10% ROI on a $2000 investment is about $40. Saving even an extra $5 a month will yield a higher return than that over the course of a year. So, if you're still in the early days of saving, focus more on getting that savings rate up before you stress over maximizing your returns.